COMMITMENTS AND CONTINGENCIES Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Nov. 30, 1998	Sep. 28, 2014	Sep. 29, 2013	Sep. 30, 2012
Commitments and Contingencies Disclosure [Abstract]
Lease expense		$ 23.5	$ 20.2	$ 21.4
Description of the contingency loss agreement	In November 1998, we signed an agreement with the three former owners of this facility whereby they have 1) reimbursed us for $0.5 million of past costs, 2) assumed responsibility for 90% of all future clean-up costs, and 3) promised to indemnify and protect us against any and all third-party claims relating to the contamination of the facility
Accrued workers' compensation liabilities		$ 1.9	$ 1.5
Allegations description		The complaint alleges, inter alia, that programmable logic devices manufactured and sold by our subsidiary Microsemi - SoC infringe United States Patent Numbers 5,687,325, 6,260,087 and 6,272,646 assigned to Intellectual Ventures II LLC, and seeks damages and other relief at law or in equity as the court deems appropriate
Defendant action		On August 8, 2011, the defendants filed a motion to stay the litigation pending conclusion of reexamination of the patents-in-suit by the United States Patent & Trademark Office.
Decision by court		The Court has not yet decided the motion to transfer or motion to stay. Discovery has not yet commenced and no trial date has been set.